While I don't claim to be an expert in solid state physics, I do know enough to find it completely reasonable that the simple measurements performed on cables don't physically tell us everything.
I have no idea what you mean by "everything." What I mean is that as cables are purely passive devices, the only effect they can have on the signal is frequency-dependent levels, aka FR. When we measure the FR of various cables, we find that it is well-explained by RLC values, and that the differences between cables are insufficient to be audible unless the RLC differences are extreme.
An audio signal has an enormous dynamic range,
Someone else inventing his own physics.
and unless the cable has been tested over signals that vary over this same range, how can you be sure that some low-level signal information isn't lost?
I dunnomaybe you could, like, measure the dynamic range somehow?
Also, how about passing a harmonically rich signal through the cable? You don't know for sure if the cable my lose some of the higher order harmonics if they are in the presence of a large magnitude fundamental.
I can't believe that someone who took physics could write such nonsense. Multiple frequencies are not "in the presence of" each other in a cable. Once again, at any given moment, the signal is alternating at only one frequency. If any frequency were "lost," there would be silence. I've never known cables to produce dropouts, have you?
Besides, this is nothing more than a thought experiment designed to establish plausibility of difference between cables that aren't evident by the basic measurements. And if it is plausible, then it is perfectly reasonable to be let subjectivity influence one's choice of cables.
A geocentric model of the universe was plausible once, too. But that's because our forebears were ignorant.